Electric heating



F. E- HA EY ELECTRIC HEAT Filed 50, 1950 FREDERICK E. HASLEY INVENTORATTO Y Patented Nov. 4, 1952 .1

ELECTRIC HEATING Frederick E. Hasley, Wilkinsburg, Pa., assignor toEdwin L. Wiegand Company, Pittsburgh, Pa., a corporation of PennsylvaniaApplication August 30, 1950, Serial No. 182,370 8 Claims. ((31. 201-63)My invention relates to electric heating, and the principal object of myinvention is to provide a suitable method of electroplating sheathedresistor electric heaters without damage from the plating solution.

In the drawing accompanying this specification and forming a part ofthis application I have shown, for purposes of illustration, twoarrangements suitable to carry my invention into practice, and in thisdrawing:

Figure l is a section through a heater of the cartridge type, showingone arrangement suitable to carry my invention into practice; and

Figure 2 is a section through the terminal portion of a heater of thetubular type, showing another arrangement suitable to carry my inventioninto practice.

The heater 50 shown in Figure 1 comprises an electrically insulatingcore I! commonly of ceramic material, a helical resistor l2 disposed onthe core H, a metal sheath l3 surrounding the core H and closed at itsrear end 14, and refractory cement I5 disposed within the sheath I3,embedding the resistor l2, and serving both to insulate the resistor andto conduct the heat from the resistor to the sheath.

In this particular heater extensions of the resistor I? are intertwistedwith additional strands, forming the terminals I6 and I1, and theseterminals are passed through apertures 18 and IS! in the body of thecore II and emerge through the open end 20 of the sheath [3.

The heater 30 indicated in Figure 2 comprises a tubular sheath 31, ahelical resistor 32 extending longitudinally of the sheath 3 I,projecting terminal pins 33 to which the ends of the resistor 32 aresuitably attached, and compacted refractory material 34 such asmagnesium oxide, embedding the resistor 32 and serving both to insulatethe resistor and to conduct the heat from the resistor to the sheath.

As will be understood, the above two heaters are merely examples, and inundertaking to electroplate any form of heater, if the plating solu-'tion reaches the refractory material the heater is at least seriouslydamaged and usually completely ruined.

To avoid this result I introduce into a space 40 at each open end of theheater H3 or 30, a body of matter 41 sufiiciently resistant to theplating solution, and of sufficient thickness, whereby the body 4!normally will not become trans-penetrated by the plating solution in thecourse of the time during which the heater is exposed to the solution.

At the present time I consider most satisfactory for this purpose asuitable uncured silicone rub- .ber, such as the product known asSilastic 120, preferably having admixed a quantity of a substancesuitable as a filler, for example, zircon round to as fine as 100 meshor finer.

Obviously the proportions in which the filler may be added, will varywith the particular materials employed, including the specific weights,but with the particular ingredients above stated by Way of example,apparently the zircon should not be greater than twice the amount of thesilastio, by weight, and preferably is in the range of 40 to per cent ofthe Whole, depending somewhat on the viscosity of the silastic.

In practice I may apply merely a suitable quantity of the material 4 ias shown in Figure l, or I may include a suitable member such as theceramic bushing 42 shown in Figure 2, serving to reduce the quantity ofthe material 4| and also to assist in compacting the material M in therespective space 40.

With the indicated composition I find that a suitable baking normallyincreased the resistance to the penetration of the plating solution, forexample, a baking at approximately 200 F. for approximately one hour.

After the heater has been plated, preferablythe material 4!, and thebushing 42 or other member that may have been included, are removed fromthe heater, and if the heater is to be sealed, a further application ismade.

On the other hand, in some instances the penetration of the solution maybe so slight that such removal is not necessary, depending partly on theparticular solution to which the material has been subjected.

As will be understood by those skilled in the art, ,various changes maybe made, within the scope of my invention, therefore my invention is notto be regarded as limited to the present disclosure, and I claim:

1. The method of preparing a sheathed resistor electric heater,including a sheath having at least one opening therein, and a resistorelement having at least one terminal accessible through the openingdisposed in said sheath and embedded in an electric insulating heattransferring refractory material, for immersion in an electroplatingsolution for electroplating the sheath, which comprises closing saidopening by introducing thereinto a body of matter consisting essentiallyof an admixture of a rubber-like material and a filler, the filler beingof a size to pass through at least a mesh screen and the aeiimooi amountof filler being not greater than twice the amount of rubber-likematerial by weight and being in the range of 40 to 60 per cent of thewhole, and baking such admixture at a temperature of approximately 200F. for approximately one hour to increase the resistance thereof to thetrans-penetration by the electroplating solution.

2. The method of preparing a sheathed re.-

sistor electric heater, including a sheath havingat least one openingtherein, and a resistor element having at least one terminal accessiblethrough the opening disposed in said sheath and embedded in an electricinsulating heat transferring refractory material, for immersion inan.electroplating solution for. electroplating the.

sheath, which comprises closing said opening'by introducing thereinto abody of matter consists ing essentially of an admixture of a rubber-likematerial and a filler, the filler being of a size to pass through atleast a 100 mesh screen and the amount of filler being not greater thantwice the amount of rubber-like material by weight and being in therange of 40 to 60 per cent of the Whole, and baking such admixture toincrease the resistance thereof to the trans-penetration by theelectroplating solution.

3. The method of preparing a sheathed resistor electric heater,including a sheath having at least one opening therein, and a resistorelement having at least one terminal accessible through the openingdisposed in said sheath and embedded in an electric insulating heattransferring refractory material, for immersion in an electroplatingsolution for electroplating the sheath, which comprises closing saidopening by introducing thereinto a body of matter consisting essentiallyof an admixture of a rubber-like material and a filler, the filler beingof a size to pass through at least a 100 mesh screen and the amount offiller being not greater than twice the amount of rubberlike material byweight, and baking such admixture to increase the resistance thereof tothe trans-penetration by the electroplating solution.

4. The method of preparing a sheathed resistor electric heater,including a sheath having at least one opening therein, and a resistorelement having at least one terminal accessible through the openingdisposed in said sheath and embedded in an electric insulating heattransferring refractory material, for immersion in an electroplatingsolution for electroplating the sheath, which comprises closing saidopening by introducing thereinto a body of matter'consisting essentiallyof an admixture of a rubber-like material and a filler, the amount offiller being not greater than twice the amount of rubber-like materialby weight and being in the range of 40 to 60 per cent of the whole, andbaking such admixture to increase the resistance thereof to thetrans-penetration by the electroplating solution.

5. The method of preparing a sheathed resistor electric heater,including a sheath having. at

least one opening therein, and a resistor element having at least oneterminal accessible through the opening disposed in said sheath and .em-

bedded in an electric insulating heat transferring refractory material,for immersion in an electroplating solution for electroplating thesheath,,

which comprises closing said opening by introducing thereinto a body ofmatter consisting essentially of an admixture of a rubber-like materialand a filler, the amount of filler being not greater than twice theamount of rubber-like material by weight, and baking such admixture toincrease the resistance thereof to the transpenetration by theelectroplating solution.

6:.The methodzof preparing a sheathed resistor electric heater;including'a sheath having at least one opening therein, and a resistorelement having at least one terminal accessible through the openingdisposed in said sheath and embedded'in an electric insulating heattransferring; refractory material, for immersion in an electroplatingsolution for electroplating the sheath, whichcomprises closing saidopening by introducingthereinto a body of matter consisting essentiallyof an admixture of a rubber-like materialand a filler, and baking suchadmixture at a temperature of approximately 200 F. for approximately onehourqto increase theiresistance thereof'to the transepenetration by theelectroplating solution;

7'. The methodi-of preparing asheathed resistor electric heater,including a sheath having atleast one opening therein;v and. aresistorelement having. at least one terminal accessible through the opening.disposed in said. sheath and.

embeddediin. an. electric J insulating heat' transferring refractorymaterial, for immersion .in an:

electroplating. solution forv electroplating the sheath, which comprisesclosing said opening by introducing thereinto a body ofmatter'consisting.

essentially of'zan admixture of a rubber-like materialand a filler, andbaking. such admixture at atemperature'of approximately 200 F. toincrease the resistance thereof to the trans-penetration bytheelectroplating solution.

8.1 The method of preparing a sheathed resistor electric heater,including a sheath having at least one opening. therein, and a resistorelement having at .least'one terminal accessible through the. opening.disposed in. said sheath and embedded in an'electric insulating heattransferring refractory material, for immersion in an electro-- platingsolution for. electroplating the sheath, which comprises closing saidopening. by introducing. thereinto a body of matter consistingessentiall'y of an admixture of a rubber-like material and a filler, andbakingsuch admixture to increase: the resistance thereof tothetranspenetration .by the electroplating solution.

FREDERICKI EL HASLEY.

REFERENCES. CITED The following-references are-of record in the fileof-thispatent:

UNITED STATES 'PATENTS Number Name Date 193,204 Wilde July 17, 1877950,777 Winslow Mar. 1, 1910 1,247,125" Madsen Nov. 20, 1917 7 1,559,860Fitzgerald Nov. 3, 1925 1,847,653 Jones -Mar. 1, 1932 2,453,562 Wright-l Nov. 9, 1948 FOREIGN PATENTS Number Country Date 461,275. GreatBritain. .Feb. 15, 1937

